Multiplexing mirror

ABSTRACT

A side view mirror including a multiplexor chip, NTC thermistor within the housing. The multiplexor controls multiple functionality from the housing and provides simplified LIN bus connection to the vehicle.

TECHNICAL FIELD

This application relates to multi-featured mirrors, particularly sideviewing mirrors for use in side view mirror assemblies for vehicles.Side view mirrors have been increasing complex with more electronicfeatures and functions in them in recent years. For instance, puddlelights, turn signals, electronic controls, heated mirror surfaces,speakers, electrochromic mirrors and electronic folding of mirrors areall features which are commonly found in side view mirrors today.

BACKGROUND OF THE INVENTION

It has become a increasing complex task to provide the proper controlsfor all of the features and to provide them in a convenient location tothe operator of the vehicle. Typically, all multifunctional mirrorsfeature a wiring harness of somewhat complex proportions havingsometimes six, seven or eight wires leading to various functions insideof the mirror housing, all of which must be controlled outside of themirror housing. This adds complexity to the vehicle assembly wherecontrollers and computer chips must be provided for in the vehicle. Thismakes mirror functionality and vehicle integration costly, complex andsomewhat burdensome from a mirror sales point of view.

Therefore, it has been a goal in the art to provide a less complex,lighter weight, and improved method for controlling mirror functions ina side view mirror.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a mirrorhaving a plurality of control features such as mirror adjustments, foldcontrols, heating, lighting, memory, turn signals, puddle lamps,electrochromic mirrors, temperature readouts and intercom functions. Themirror of the present invention includes amirror housing andmultiplexing chip contained within the housing. The multiplexing chipincludes a three-wire connection to a control interface inside thevehicle forcontrol of the features.

A second aspect of the present invention is that the multiplexing chipis advantageously used to provide a controlled memory position of themirror surface in the housing. In this respect, a pair of motors areused for controlling and positioning the x and y coordinates of themirror surface. A signal is read by the multiplexing chip for eachrotation of each of the motors. Prior to returning the motors toapreprogrammed memory position, the motors are indexed to a full x or ycoordinate endpoint, and thereafter the multiplexor can index the motorto its end position and bring it back to the proper memory position bymeasuring the turns of the motor. In this manner, if for some reason themirror has become misaligned, the multiplexing chip will return themirror to the proper position by this indexing function each time priorto returning to a preprogrammed memory position set forth in themultiplexing chip.

Additionally, the multiplexing chip allows for multiple mirrorfunctionalitycontrol with only a 3 wire lead into the vehicle,simplifying controls within the vehicle. Use of the multiplexor within amirror housing also allows the placement of an NTC or PTC thermistorwithin the housing, to provide in-housing temperature compensation tothe electrical systems such as the mirror motors and to read the outsidetemperature. This also allows accurate control of the mirror motors viapulse width modulation from the multiplexor chip.

Further understanding of the present invention will be had in view ofthe description of the drawings and detailed description of theinvention, when viewed in conjunction with the subjoined claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a mounting plate with two discrete driveassemblies installed the mounting plate;

FIG. 2 is a cross-section of a mounting plate and rear view mirrorassembly along section 1—1 of FIG. 1;

FIG. 3 is a schematic view showing the motor rotational pickup and theand the peak signals read by the multiplexor chip;

FIG. 4 is a schematic view of the multiplexor chip;

FIG. 5 illustrates a mirror having an x and y axis for use in analternate embodiment;

FIG. 6 is a sectional view along axis y—y of FIG. 5; and

FIG. 7 is a sectional view along axis x—x of FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a plan view of the inside of a mirror housing 10 having amounting plate 12. The mounting plate has a number of recesses 14, 16,18 and 20 for the fitment of various parts, such as for example adiscrete drive assembly 22 (FIGS. 1 and 2) in recess 14 and a likediscrete drive assembly 24 (FIG. 1 only) in recess 16.

The discrete drive assembly 22 comprises a cover 26 the uppermostsurface of which is housed an electric motor 28 shown in phantom. Themotor has a worm screw 30 attached to its output shaft.

The worm screw 30 engages with a jacking screw 32 having a ball head 34at its upper end for engagement with the rear view mirror 36 as depictedin FIG. 2. As the worm screw is moved longitudinally along islongitudinal axis, in and out of the recess 14, the mirror moves aboutthe pivot 38 in an axis orthogonal to the vertical plane lying along theline 1—1 of FIG. 1.

The same arrangement is provided by discrete drive assembly 24 whichcreates a movement of the mirror about the pivot 38 in an axisorthogonal to the vertical plane lying along the line 2—2 in FIG. 1.

Both electric motors are controlled remotely by the driver of thevehicle and, in some, but not all mirrors, the mirror position isadjusted using only one motor such as mono-axis mirror assemblies. Theinvention to be described in greater detail is useable with those havingone or two position adjusting motors. Such motor positioning systems areshown in U.S. Pat. No. 4,881,418 to Fimeri, issued Nov. 21, 1989, whichis hereby incorporated by reference.

As set forth above and in accordance as specified that the presentinvention is a method for position of the mirror 10. The mirror includesa reflective surface 36 and carrier assembly 38 attached to the mirrorsurface and is included at least the first motor such as such 26 foradjusting the angular orientation of the mirror by the motor.

The shaft 40 of the motor in FIG. 3 is monitored by measuring the peaksin current as the motor shaft rotates along the brushes 42 and 44. Thus,the number of peaks such as shown at a, b, c, etc. are counted by amultiplexor. Thus, a signal (a, b, c . . . ) for each rotation of themotor shaft is measured. The rotational shaft is measured between afirst position and a second position preferably the stop positions oneither (preferably both) of the x or y axis of the mirror movement todetermine the number of rotations of the shaft (peaks a, b, c . . . )between the first stop position and the second. In order to provide aproper positioning of the mirror position between the first and secondposition, a base point for positioning the it mirrors established bydriving the motor to a stop at one of the first or second positions andthereafter actuating the motor to a predetermined position between thefirst and second positions. Each of the motors 24, 26 is actuated thisway to provide accurate memory positions for the mirror.

In the present invention, a multiplexing chip 42 is provided whichmeasures the peaks of motors 24 and 26, and allows control of the x andy position of the mirror assembly, in order to allow memory functionwithout any recopy potentiometer.

Referring now to FIG. 4, the multiplexing chip is connected to variousfunctional features found in the mirror which are selected from thegroup of a fold control, heating of the mirror, security lighting, turnsignals, stop signals, alarms, intercom functions, light sensors,keyless entry, image capture device, compass, intelligent vehiclehighway system, global positioning system, garage door opener, orcombinations thereof, and, of course, x and y coordinate positioning ofthe mirror. The use of the multiplexing chip allows for control of allthese functions by way of a serial bus, LIN connection to a controller45. Thus, because of the use of the multiplexing chip, all of thesefunctions can be controlled by way of a serial input/output line 46along with a ground line 48. Thus, with the serial bus line 46 in apreferred embodiment, the mirror folding can be controlled as shown at52. Memory positions can be stored for the x-position 54 and y-position56 of the mirror surface. Additionally, at 58, the memory fold positionsmay be provided for purposes of alarms or the like. Mirror heating ofthe mirror could be controlled such as at 60.

In a preferred embodiment, an NTC thermistor 62 is provided formeasurement of temperature. As will be readily appreciated, thethermistor 62 may be linearized by the multiplexor which removeslinearization systems outside of the mirror as required in prior artdesigns. Thus, with the NTC multiplexor combination for specifiedtemperatures, less inputs are necessary and less external controlmechanisms are necessary allowing the NTC to be positioned andcontrolling various temperature sensitive items within the mirroritself. By use of the multiplexor, the NTC output can be linearized andmirror control in accordance with temperature such that the x and ymotors provide constant speed no matter what the temperature.Additionally, dual speed mirror fold functions may be provided with theuse of the multiplexor.

Additionally, the use of a multiplexor allows for additionalfunctionality to the mirror, such as temperature controlled mirrorheating. For instance, in another aspect of the invention, an alarmfeature could be connected to the multiplexor. In the alarm feature, ifan unauthorized entry is conducted without, for instance, a key sensedin the door lock or a wireless key fob signal sensed, the multiplexorcould be programmed to have a flashing light or the light go off and/orprovide folding of the entire mirror and lock the entire mirror in thefolded position until the key fob is actuated or a key is used in thedoor. This allows additional security for the vehicle.

In a preferred embodiment, a Motorola power chip with AMP connections isutilized. For instance, a suitable Motorola power chip, Model No.M05Br06 is utilized. Additional functionality is provided in that thelogic of a power fold mechanism could be included in the chip whichreduces the cost of the power fold mechanism and could be utilized tohave two speeds of power fold. The circuit is also configured in analternate embodiment to be auto diagnostic, providing signals if thecomponents are working incorrectly. Also, with respect to the power foldmechanism, the chip is programmed to sense overcurrent and would allowthe power fold to discontinue upon, for instance, hitting an object orthe like, and may provide other functionality. Additionally, as setforth above a telecommand module may be connected directly to the powerchip for door opening and the like thereby increasing functionality andreducing cost.

A conventional control panel may be utilized for control of thefunctionality in the mirror. Thus, standard user controls forcontrolling the mirror angles and the predetermined memory positions areinterfaced into the multiplexing chip through the serial bus interface.However, in the present invention, the memory is retained in the mirroritself by way of the multiplexor rather than an external unit within thevehicle. Thus, assembly of the vehicle is advantageously improved.

Referring now to FIGS. 5-7, a method of permanization of the mirrorposition without the benefit of a separate potentiometer is shown. Inthis method, the zero position of FIG. 5, Y′OY X′OX may be found bymeasurement of the ripple current of the electrical motor collector oneach axis. In this discussion, y and x represent the number ofelectrical motor rotations for the distance between steps along Y′OY andX′OX. The stored zero position is +Y₁ rotations for the position vectorOY and −Y₂ for OY′. Similarly, for the position OX, the number ofrotations is +x₁, and for OX′, the number of rotations is −x₂.

Most mirrors include override positions which, if the mirror is bumped,will move the position of the mirror and the reference position willdisappear since the angles of the mirror are wrong upon impact ormovement of the mirror surface. In the subject example, the mirrors maybe rotated 12° on either axis. This input is memorized in the chip. Ribs1 and 2 are provided for limits on the movement for the y position, andstops 3 and 4 provide limits on movement for the determination of theposition of x. Thus, in operation, the memorization features alwaysproceed from the midpoint zero position O. The midpoint zero position Ois memorized by allowing the mirror first to go to rib 1 and then aftergoing to rib 2 and memorizing the motor rotations. Thus, the middle orzero position is y/2 (designated y_(m)). Thereafter, the mirror ispositioned at yand the same positioning is used on the x axis. Thus, themirror goes to rib 3 and then proceeds to rib 4, and the number of turnsis memorized. The midpoint of this is memorized by x/2, which isdesignated as x_(m). Thereafter, the mirror repositions itself atx_(m)Y_(m) by going to a stop position at the zero position and seekingthe memorized position from this zero position.

Thus, the memorized position is always measured from the x_(m)Y_(m)position. Each time a memory of the mirror is desired, the mirrorpositions itself in accordance with this procedure and, thereafter, willmeasure the mirror prize position from the x_(m)Y_(m) position.

In practice, adjustment may be made by a high speed motor to reduce theadjustment time, preferably to less than 5 seconds. In addition, forimproving the accuracy of the mirror position and the memory position,dispute of traveling during positioning will be decreased using pulsewidth modulation of the current to position slightly before thememorized position, wherein the memorized position can be accuratelydialed into place. For example, the high speed motor could be used up toabout 4° before the memorized position and, thereafter, slowly broughtinto the proper position in the mirror housing. Thus, using this method,it is not necessary to have a separate potentiometer in the mirrorassembly for providing feedback as to the position of the mirror. Thisreduces the cost of the mirror and provides an accurate positioningsystem with less inputs. This results in a simplified wiring harness.

Those skilled in the art can now appreciate from the foregoingdescription that the broad teachings of the present invention can beimplemented in a variety of forms. Therefore, while this invention hasbeen described in connection with particular examples thereof, the truescope of the invention should not be so limited, since othermodifications will become apparent to the skilled practitioner upon astudy of the drawings, specification and following claims.

What is claimed is:
 1. A method for positioning a mirror comprising: (a)providing a mirror including a reflective surface; (b) a carrierassembly attached to said mirror surface, said carrier assemblyincluding a motor having a shaft for adjusting an angular orientation ofthe mirror by said motor; (c) a signal pickup for electrically pickingup a signal for each rotation of the motor shaft; (d) measuring therotation of the shaft between a first position and a second position ofthe mirrors for providing a position index for positioning saidreflective surface at any predetermined point between said first andsecond position; and (e) establishing a base point for positioning ofsaid mirror surface by driving the motor to a stop at one of said firstand second positions and thereafter actuating said motor along saidposition index to a predetermined position between said first and secondpositions.
 2. The method of claim 1 further comprising providing amultiplexing chip for providing positioning of the mirror.
 3. The methodof claim 2 wherein said multiplexing chip stores one or severalpredetermined positions for said mirror surface in memory.
 4. The methodof claim 2 further comprising a second motor for adjusting said mirror,wherein said motor and said second motors provide for adjustments in anx and y direction, said multiplexing chip monitoring and memorizing therotations of the motors for determining position.
 5. The method of claim4 further comprising an NTC thermistor for compensating for temperaturevariations in the electrical signal.
 6. The method of claim 4 whereinsaid multiplexor also controls mirror functions selected from the groupconsisting of fold control, heating of the mirror surface, lighting,turn signals, alarms, intercom functions or combinations thereof andwherein said multiplexor includes a wiring harness into a vehicleconsisting of three wires.
 7. The method of claim 6 wherein said wiresinclude positive power, a negative or ground wire and a serialconnection wire.
 8. The method of claim 7 wherein said serial connectionwire is connected to a controller.
 9. The method of claim 8 wherein saidmultiplexing chip is sealed in a housing and mounted in said mirrorhousing.
 10. A method for positioning a mirror comprising: (a) providinga mirror including a reflective surface; (b) a carrier assembly attachedto said mirror surface, said carrier assembly including a first motorfor adjusting the angular orientation of the mirror by said motor; (c) asignal pickup for electrically picking up a signal for each rotation ofthe motor shaft; (d) measuring the rotation of the shaft between a firststop position and a second stop position along either a first or secondaxis and averaging the result to provide a zero position index forpositioning said reflective surface at any predetermined point betweensaid first and second position; and (e) establishing a base point forpositioning of said mirror surface by driving the motor to said zeroposition, and thereafter actuating said motor to a predeterminedposition between said first and second positions by advancing the motorfrom said zero position to said predetermined position.
 11. The methodof claim 10 further comprising providing a multiplexing chip forproviding positioning of the mirror.
 12. The method of claim 10 whereinsaid multiplexing chip stores one or several predetermined positions forsaid mirror surface in memory.
 13. The method of claim 10 wherein asecond motor is provided for adjusting said mirror, said first andsecond motors providing for adjustments in an x and y direction, saidmultiplexing chip monitoring and memorizing the rotations of the motorsfor determining position, and wherein said zero position is establishedon both axes.
 14. The method of claim 13 wherein an NTC thermistor isused to compensate for temperature variations in the electrical signal.15. The method of claim 13 wherein said multiplexor also controls mirrorfunctions selected from the group consisting of fold control, heating ofthe mirror surface, lighting, turn signals, alarms, intercom functionsor combinations thereof and wherein said multiplexor includes a wiringharness into a vehicle consisting of three wires.
 16. The method ofclaim 15 wherein said wires include positive power, a negative or groundwire and a serial connection wire.
 17. The method of claim 16 whereinsaid serial connection wire is connected to a controller.
 18. The methodof claim 17 wherein said multiplexing chip is sealed in a housing andmounted in said mirror housing.